Text and Data Mining valid from 2018-06-26
Received: 4 April 2018
Accepted: 5 June 2018
First Online: 26 June 2018
Ethics approval and consent to participate
: This study was approved by the Ethical Committee of the Johannes Kepler University Linz (Linz, Austria) and carried out according to the Declaration of Helsinki. All study participants gave their written informed consent.
: The authors declare that they have no competing interests.
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